Birth control pills are the most popular female contraceptive and are said to be used by more than 80 million women worldwide to prevent pregnancy. However, it is important for every woman and her partner to understand how they work, before opting for them. This article provides information about the mode of action of these pills.
The development of the birth control pill in the 1960s was proclaimed a medical breakthrough by feminists, as it offered women a practical solution to prevent conception. The initial opposition ‘the pill’ faced from the government and other organizations no longer stands and its use has become common in modern times. In order to understand how do these pills work, one needs to have a proper understanding of the female reproductive cycle.
The Female Reproductive Cycle
The woman’s reproductive system has 2 ovaries, which contain thousands of follicles within which are immature eggs. When her menstrual cycle begins, the pituitary gland releases FSH (follicle stimulating hormone) which stimulates the immature eggs (follicles) to develop. Usually only one egg reaches maturity each month. While this growth is taking place, the cells around the egg produce the female hormone estrogen, which in turn begins to prepare the uterus for the fertilized egg by thickening its lining.
The rising level of estrogen in the blood signals the pituitary gland that the follicle has achieved a certain size and the ovary is ready to release the egg. The pituitary gland in turn releases a high level of LH (luteinising hormone), which alerts the ovary to release the egg. Thus, the follicle bursts to release the egg and then the egg makes its journey through the fallopian tube to the uterus. Once in the uterus, it may be fertilized by sperm, resulting in pregnancy.
The cells that formed the follicle (now called a corpus luteum), begin to produce the hormone progesterone. In the event of fertilization, progesterone keeps being produced, which keeps the egg implanted and growing. However, if fertilization does not occur, the corpus luteum stops producing the hormone. When levels of progesterone and estrogen fall, they cause the lining of the uterus to break and release, along with the unfertilized egg. The cycle then starts all over again.
Birth Control Pills: How Do They Work?
The pills induce slow release of reproductive hormones, that suppresses ovulation. As we have seen, when ovulation takes place, the egg is released from the ovaries. However, if ovulation is suppressed the egg is not released, and hence, there is no possibility of pregnancy.
Birth control pills come in two forms, the combined pill and the mini pill. The mini pill contains only progestin (synthetic progesterone), while the combined pill comprises both synthetic estrogen and progestin. Along with preventing ovulation, the mini pill also causes thickening of the mucous around the cervix, which acts as a barrier and discourages sperm from entering. Also, it acts on the lining of the uterus, which makes it difficult for the fertilized eggs to implant into the uterus wall.
The mini pill needs to be taken daily and one is not likely to have a period while on the pill. However, if you do have a period, it means that you are still ovulating, which increases the chances of pregnancy. The combination birth control pills are available in 21 or 28-day packs. For women using the 21 day pack, they have the option of not taking the pill for 7 days after the pack ends and then resuming them. 28-day packs contain 21 pills containing reproductive hormones and 7 placebos. A woman’s period will occur during the week she takes the 7 placebos.
If you are still wondering how well do birth control pills work, the FDA says that they are 90-95 % effective if one misses a dose or takes it at a different time each day. However, if taken at the same time every day, they are 99% effective. As to how fast do birth control pills work, be aware that most doctors will recommend that you use additional contraception, up to 15 days or a month after you start taking the pill. It is also essential for you to understand the risks involved before you start taking them.